Electronic warfare systems are used on modern military aircraft as part of their offensive and defensive capabilities. These electronic warfare systems emit RF signals that travel through space. Radar systems use RF emissions to locate and track opposing aircraft and some radar systems are incorporated within missiles to assist in the self-guided propulsion of a missile to its target. An electronic warfare search receiver is used defensively to detect those RF emissions. The receiver searches the range of frequencies (the RF spectrum) in which the RF emissions are likely to occur. The receiver then detects and analyzes the nature of the RF signals. By determining the characteristics of the signals received, the defender will know the nature of the threat and, for example, will know if a radar guided missile has "locked on" to the defenders aircraft. These systems are used in friendly as well as unfriendly aircraft. In a tactical or strategic environment, the number of aircraft and the density and diversity of the emissions in the RF spectrum is quite large and is expected to increase. Existing and future aircraft and other platforms need advanced capability avionics in order to successfully perform and survive on future missions. There will be more electromagnetic emitters from friendly, allied and enemy sources and all of these sources must be detected, analyzed and sorted. These RF receivers need to be more available (longer mean time between failure) then ever before so that the equipment will perform on every mission because success can only be achieved if the aircraft has operating equipment.
Channelized receivers are recognized as a preferred solution to provide very high probability of intercept even in extremely high density environments. They provide wide instantaneous bandwidth while maintaining dynamic range, high frequency resolution and direction finding capabilities. The channelized receiver achieves this performance by paralleling many narrow bandwidth receivers together into a coherent whole. However, true channelized receivers (processing the entire instantaneous bandwidth simultaneously) have generally been impractical to date. The RF and digital circuitry required to process 100 "receivers" is too large and heavy and consumes too much power.
A small, lightweight, low power channelized receiver is needed to meet the needs of future tactical aircraft, helicopters and surveillance platforms. Also, a small channelized receiver is crucial for upgrading the electronic warfare (EW) capabilities of existing aircraft.
It is unlikely that a single receiver type will be capable of meeting all offensive or defensive threat detection and analysis requirements dictated by the future electronic warfare environment. Instead a set of search and analysis receivers of complimentary capabilities are likely to be required to meet future demands. Trade offs between probability of intercept, bandwidth, simultaneous signal resolution, sensitivity, receiver complexity and power consumption are necessary. It would be advantageous to have a small lightweight, low power channelized receiver. Such a receiver could process signals digitally in real time and have the flexibility of being programmable so that various portions of the channelized receiver can be used for multiple purposes. In such a receiver it would useful to have the ability to eliminate all spurious signals while maintaining a high probability of intercepting real signals.